dog wont pick up duck?

I have a 9 year old black lab he has been a great retriever last 8 years. He has played fetch since a pup in yard with a tennis ball and dad trained him with a rubber bumper. This year he go out great for duck but gets to it and wont bring it back just smells i or lick it and leave it there and come back i have no idea what happened. he still will play fetch at home with bumper. we but some duck wings on bumper and he wont pick that up either any advise/tips will be appreciated

Not sure if this will work in your situation (or what happend to be honest), but this is what I did when training mine when he was a pup. He was hesitant to pick up birds the first few times so I didn't try to force them on him. Instead, I put a sock over his bumper and had him retrieve that for a couple of weeks. I then took the same sock and stuffed a dead duck in it.

(Note- the duck was kept in the freezer between sessions and only thawed enough to not be freezing to the touch)

After a week or so, I cut a hole and pulled the head through. A week later, I cut the sock into an 8" band around the middle of the bird. Subsequently I cut about 2 inches off each week until all I had left was a little ring of sock. Finally, I had him retrieve without the sock. He never noticed it was gone.

This worked for me and I haven't had an issue since, but like I said, the circumstances are a bit different.

Jacob, I had the same issue with 4-year-old lab. She was a fantastic retriever, had great attention span, would fetch bumpers and even training decoys for hours on end, but she would not bring me back a downed duck. She would even swim out to the bird, sniff it, then swim back empty "mouthed". I finally got frustrated and put her in force fetch training. It took 4 months, but I just got her back and she is retrieving birds, from the water and out past decoys, with no issues at all. The real test will happen this weekend during our season opener, but I feel confident that she will do well. FF might be something you can try out if the sock trick does not pan out.